Motor-driven, telescoping antenna for automobiles

ABSTRACT

A motor-driven, telescoping antenna comprising an electric motor having an opening through the center of its armature. Slidable vertically through the opening is a metal tube that forms the antenna rod. A helically coiled steel spring is fixed to the bottom end of the antenna tube and extends downwardly therefrom. Passing through the coils of the spring is an angularly bent pin having a horizontal arm fixed to an annular bushing surrounding the coil, and a vertical arm that extends lengthwise of the spring down through the center thereof. The bushing is mounted on the inside of a tubular drive shaft that is fixed to the bottom end of the motor armature. The tubular shaft turns with the armature, causing the angularly bent pin to drive the helical spring upwardly or downwardly, carrying the antenna rod with it. The spring has bridges across adjacent coils at opposite ends, which engage the pin to prevent jamming of the motor. A limit switch turns the motor off when the antenna rod has reached the end of its travel during extension or retraction.

MOTOR-DRIVEN, TELESCOPING ANTENNA FOR AUTOMOBILES [76] Inventor: Otto Schuscheng, Scharnhorstrasse 4, 509 Leverkusen, Germany [22] Filed: July 24, 1972 [21] Appl. No.: 274,316

[52] US. Cl. 343/903 [51] Int. Cl. H0lq 1/10 [58] Field of Search 343/901, 903

[56] References Cited UNITED STATES PATENTS 2,580,889 1/1952 Carlson 343/903 2,763,340 9/1956 McDonnell et al. 343/903 2,953,934 9/1960 Sundt 343/903 2,926,35l 2/1960 Wise 343/903 Primary Examiner-Eli Lieberman Attorney, Agent, or Firm-Herbert E. Kidder [57] ABSTRACT A motor-driven, telescoping antenna comprising an I electric motor having an opening through the center of its armature. Slidable vertically through the opening is a metal tube that forms the antenna rod. A helically coiled steel spring is fixed to the bottom end of the antenna tube and extends downwardly therefrom. Passing through the coils of the spring is an angularly bent pin having a horizontal arm fixed to an annular bushing surrounding the coil, and a vertical arm that extends Iengthwise of the spring down through the center thereof. The bushing is mounted on the inside of a tubular drive shaft that is fixed to the bottom end of the motor armature. The tubular shaft turns with the armature, causing the angularly bent pin to drive the helical spring upwardly or downwardly, carrying the antenna rod with it. The spring has bridges across adjacent coils at opposite ends, which engage the pin to prevent jamming of the motor. A limit switch turns the motor off when the antenna rod has reached the end of its travel during extension or retraction.

1 Claim, 2 Drawing Figures Apr. 9, 1974 PATENTED PR 9 I974 MOTOR-DRIVEN, TELESCOPING ANTENNA FOR I AUTOMOBILES The present invention pertains to a motor-driven, telescoping antenna for use in automobiles, which is extended and retracted by an electric motor having a limit switch, and using a driving means comprising a helical spring wound from steel wire. More specifically, the invention is concerned with the arrangement of the motor and spring which serve to extend and retract the antenna.

It is known that motorized antennas whose drive is arranged under the antenna are difficult to install in the car and become trouble-prone due to water entering the drive housing.

These disadvantages are eliminated in this motorized antenna. The drive of the antenna is slipped over the antenna rod. This has the advantage that the drive can be accomodated better in the automobile upon installation, the motorized antenna becomes shorter, and no water gets into the bearing points of the motor.

' scoping parts of the antenna, the coil spring a is yield- The preferred embodiment of the invention is illustrated in the accompanying drawings, to which reference is had in the following description.

FIG. 1 is a sectional view through a motor-driven, telescoping antenna embodying the invention; and

FIG. 2 is a further enlarged, fragmentary sectional view, showing the pin engagement in the helical steel spring.

In the drawing, the reference character M designates an electric motor enclosed within a housing H, which is mounted in any suitable manner on the body of an automobile (not shown). The motor M includes the usual armature A, which rotates about a vertical axis, and at the bottom end of the armature is a commutator i. The armature has a central bore, through which passes a continuous metal tube that is covered at the top with plastic and thus becomes an antenna rod. This metal tube serves at the same time as suspension of the armature and internally to receive the telescoping parts.

The extending of the telescoping parts occurs in the lower portion in the antenna rod by means of a long helically coiled steel spring a and an angularly bent pin b which in a bushing c is mounted fast in the motor shaft.

The extending and retracting of the telescoping parts occurs in the lower antenna rod f by means of a long steel spring a and an angularly bent pin b having a horizontal arm that is fixed to bushing c mounted in the bottom end of tubular shaft d. Bent pin b extends between coils of steel spring a, and the vertical arm of the pin ingly held against turning by frictional contact with the surrounding stationary part, and the spring a is thus raised or lowered by the horizontal arm of bent pin b as the latter revolves with the armature. When pin b strikes the bridge h it causes the spring a to revolve with it. Limit stop extension e1 is supported for rotational movement relative to the surrounding lower antenna rod f, and is connected to spring a by means (not shown) which causes the extension e1 to turn with the spring when the latter starts to revolve at the end of its linear travel in either direction. Turning of the switch extension e1 relative to the housing H causes the limit switch e to turn off the motor M.

The lower end of the steel spring a is inserted into a flexible tube 1 and can be installed in the car as desired. The extending and retracting of the steel spring a by pin b has the advantage that the motor cannot jam by bridge h and becomes less prone to disorders due to dirt.

I claim:

1. A motor-driven, telescoping antenna for automobiles, comprising an electric motor having a rotatable armature; an extensible antenna rod passing through the center of the armature and slidable freely with respect thereto, a helically coiled spring (a) fixed to the bottom end of said antenna rod; a rotatable drive tube (d) attached to the bottom end of said armature and rotatable therewith; an angularly bent pin (b) fixed to the bottom end of said drive tube and having one horizontal arm extending between coils of said spring, and a vertical arm extending longitudinally through the center of the spring; said spring having bridges (h) extending between adjacent coils at each end thereof, said bridges being engaged by said pin (b) at the end of the linear travel of said spring during extension or retraction of the antenna, thereby causing said spring to start turning; and a limit switch (e) having a tubular extension (e1) which surrounds said drive tube (d) and spring (a); said extension (e1) being turned by said spring when the latter starts to rotate, thereby actuating said limit switch to switch off the motor. 

1. A motor-driven, telescoping antenna for automobiles, comprising an electric motor having a rotatable armature; an extensible antenna rod passing through the center of the armature and slidable freely with respect thereto, a helically coiled spring (a) fixed to the bottom end of said antenna rod; a rotatable drive tube (d) attached to the bottom end of said armature and rotatable therewith; an angularly bent pin (b) fixed to the bottom end of said drive tube and having one horizontal arm extending between coils of said spring, and a vertical arm extending longitudinally through the center of the spring; said spring having bridges (h) extending between adjacent coils at each end thereof, said bridges being engaged by said pin (b) at the end of the linear travel of said spring during extension or retraction of the antenna, thereby causing said spring to start turning; and a limit switch (e) having a tubular extension (e1) which surrounds said drive tube (d) and spring (a); said extension (e1) being turned by said spring when the latter starts to rotate, thereby actuating said limit switch to switch off the motor. 